before adding cryptoshuffler

pwgenerator/funcs.go

@@ -1,12 +1,37 @@
 package pwgenerator
 
 import (
-	"bytes"
 	"crypto/rand"
 	"math/big"
 	"sort"
+	"strings"
 )
 
+/*
+	GetCharset returns a CharSet from a set of characters.
+
+	chars can be one of []rune, []byte, []string, or string.
+*/
+func GetCharset(chars interface{}) (charset CharSet, err error) {
+
+	switch t := chars.(type) {
+	case []rune:
+		charset = CharSet(string(t))
+	case []byte:
+		charset = CharSet(string(t))
+	case []string:
+		s := strings.Join(t, "")
+		charset = CharSet(s)
+	case string:
+		charset = CharSet(t)
+	default:
+		err = ErrBadType
+		return
+	}
+
+	return
+}
+
 // sortDedupe sorts a slice of runes and deduplicates them.
 func sortDedupe(charset *CharSet) {
 
@@ -42,12 +67,16 @@ func sortDedupe(charset *CharSet) {
 */
 func saferRandInt(max int) (randInt int, err error) {
 
+	// Avoid a panic on max being 0 per rand.Int.
+	if max == 0 {
+		max = 1
+	}
+
 	var max64 int64 = int64(max)
 	var cryptoInt *big.Int = big.NewInt(max64)
-	var cryptoReader *bytes.Buffer = new(bytes.Buffer)
 	var randInt64 int64
 
-	if cryptoInt, err = rand.Int(cryptoReader, cryptoInt); err != nil {
+	if cryptoInt, err = rand.Int(rand.Reader, cryptoInt); err != nil {
 		return
 	}